Loud-speaker



N. BALDWIN LOUD SPEAKER Sept. 3, 1929.

Filed Aug. 16, '1926 M 3m INVENTOR Patented Sept. 3, 192.9.

UNITED STATES PATENT OFFICE.

LOUD-SPEAKER.

tA pplicationfiled August 16, 1926. Serial No. 129,459.

The present invention appertains to loud speakersand particularly tothose in which large diaphragms or sound boards are used to producethesound;

The principal obj ect is to provide a simple I attain this and otherobjects by the mechanism illustrated in the accompanying drawing inwhich Fig. 1 is a section of the instrument as applied to a sound hoardsuch as a panel of a door, and Fig. 2 is an elevation of part of thestructure shown in Fig. 1

Numeral 1 designates the armature to be usedand numeral QVdesignates aspool hav ing a, central tubular portion and containing the actuatingcoil. The armature passes centrally through the tubular portion of thespool and is connected-internally with said spool by means of a flexiblefulcrum 3 consisting of a piece of sheet metal ribbon bent at angles soas to provide a straight part connecting the armature with the spoolcenter and fiat surfaces at e-itherend to fasten to the armature andspool center.- The middle part of this fulcrum ribbon maybe made moreflexible by perforating it and cutting away portions as indicated inFig. 2. Thespool is held position by U-shaped polepieces 4 and 5 which"are secured to the Q poles'of the horeshoe magnet 6. In the-structure ashere illustrated the magnet 6is se- .cured to a bar 7 by means of ascrew 8 and cross bar 9,'and the bar 7 is secured-to a door by means ofthe screws 10, 11 and 12. The

49 screw 11 passing through the bar 7 is-tapped into the door 13 andcarries a-coil spring 14;

which tends to press the bar 7 against thedoor 13. The position of thebar 7 is adjustable by means of the screw 12. I

A link 15 attached to the armature and having an enlarged portion at oneend presses upon the panel 16 and communicates the vibration of thearmature to the panel. -A pressure upon the link 15 is maintained by aspring 17 seated in the polepiece 4t and pressing against the armature.It will be seen that the position of the armature between the polespieces is adj ustableby means of the screw 12. I claim:

said spool.

operated armature fulcrumed within the spool, anda fulcrum of sheetmetal, upon which said armature is permanently mounted. 2. A loudspeaker comprising a spool, an actuating coil on saidspool, an operatingarmature within said spool, and a fulcrum of sheet metal nondetachablyconnected to said armature and to said spool.

. 8. A loud speaker comprisinga spool, an actuating coil on said spool,an operating armature within said spool, and a fulcrum of sheet metalfixed to said armature and to ft. A loud speaker comprising aspool, anactuating coil on said spool, an'operating armature within said spool, afulcrum of sheet metal for said armature and within said spool,

a sound producing element, and a link in operative relation with saidarmature and said sound producing element, said link being disposed atan obtuse angle with said armature.

5. A loud speaker comprising a spool, an actuating coil on saidspool,,an operating armature within said spool, a fulcrum of sheet metalfor said armature and within said spool, a soundboard, and a link inoperative relation with said armature and said soundboard, said linkbeing disposed at an obtuse angle with said armature.

6. A loud speaker, comprising an actuating coil, a sheet metal fulcrumwithin said coil, and an armature mounted on saidfulcrum, the saidfulcrum being disposed obliquely to said armature.

7. A loud speaker,.com prising an actuating coil, a fulcrum within saidcoil, and an armature mounted on said fulcrum, a portion of said fulcrumbeing non-parallel to said armature and being so; arranged with respectto said armature that functioning of said, fulcrum imparts alongitudinal motion to said armature. p

- 8. A loud speaker, comprising an actuating coil, a fulcrum within saidcoil, and an armature mounted upon said fulcrum, the

said fulcrum being formed of a strip of sheet metal having a flexingportion. disposed obliquely to said armature.

ATHAME BALDWIN.

